This invention relates generally to controlling access to enclosures and particularly to security devices for insulated doors. More specifically, the present invention is directed to lock assemblies which are suitable for use on access doors of walk-in storage compartments such as refrigerators and freezers of the type used in the commercial preparation of food. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
While not limited thereto in its utility, the present invention is particularly well suited for use on the insulated doors of walk-in refrigeration apparatus of the type employed in the restaurant industry. Commercial walk-in freezers and refrigerators commonly contain meat and other food products that are subject to damage if not properly refrigerated. Therefore, such refrigeration apparatti must have a latch mechanism which will ensure that their access doors securely latch when closed. Additionally, products such as meat and fish are valuable commodities and thus subject to theft. The doors of commercial walk-in freezers, accordingly, will desirably have a locking mechanism to prevent unauthorized entry. Optimally, such locking mechanisms will automatically lock the door each time it is closed. Further, safety considerations dictate that a lock for the door of a walk-in freezer or the like be operable from the inside of the freezer without a key to insure that personnel can not be accidently or deliberately locked in the refrigeration compartment.
Currently available freezer door lock assemblies are configured to be mounted on the outside surface of the door and, although generally available with some form of safety release from the inside, are not self locking. The outside mounting also exposes the strike, latch and handle to tampering and defeat of the lock assembly. The currently available lock assemblies generally rely on the use of a padlock for locking. Even those units with a built in lock cylinder have padlock provisions which demonstrates their design inadequacy.
The preferred configuration for any door locking device is to locate the latch or bolt and its related mechanism within the door or on the inside door surface to prevent or resist defeat from the outside. The only exposed components should be limited to those which are necessary for appropriate operation.
Because the doors of walk-in freezers are typically a sandwich construction, comprising a layer of foam between layers of relatively thin sheet metal, the door structure would be insufficient to provide adequate support for a lock installation within the door. Further, any significant displacement of the insulating foam would affect the insulating and structural properties of the door.
Mounting a locking device on the inside surface of the freezer door has, until now, been avoided because of the risk of frost and ice build up which would prevent proper Operation and cause a lock-in or lock-out.